The described aspects relate generally to wireless communication systems. More particularly, the described aspects relate to techniques for radio link status reporting.
Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems. These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level.
An example telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectral efficiency, lower costs, improve services, make use of new spectrum, and better integrate with other open standards using OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.
In wireless communication systems employing LTE, a user equipment (UE) served by one or more eNodeBs may occasionally tune away a radio receiver from one frequency, radio access technology (RAT), and/or air interface related to a different subscriber identity module (SIM) in order to monitor another frequency, another RAT, and/or another air interface associated with a second SIM. During a tune away, reception performance of the UE on the initial frequency may be reduced, resulting in an increased number of missed or incorrectly received data packets. If the UE is unable to retransmit and recover the missed or incorrectly received data packets at lower protocol layers, e.g., through retransmission requests, then higher layer protocols, such as transmission control protocol (TCP), may experience higher round trip times, resulting in a disproportionate decrease in throughput.
Therefore, there is a desire for improvements in techniques for reporting the status of missing data packets at lower protocol layers of the UE, especially when a relatively large number of data packets are affected by an event such as a tune away.